Electrical conduit fitting



Jan. 15,1946. I v n A.,o|- EvlN. 2,392,940

ELECTRICA@ CONDUIT FI'TTIIG Filed Aug. 5, 1945 2 Smets-sheet 1 rml-m.

mmumwwuilwnlimm, a? as@ u I migo-la 28 HDDLPH DLEV/N INVENTOR @www ATTORNEY A.' opl-:VIN

2 Smets-sheet,J 2

HDDLPH LEV/N INVENTOR ATTORNEY Jan. 15,1946.

'ELECTRICAL Coup/UIT FITTING Filed Augf 5, 1943 Y vention lies the-provision A readily adapted for indoor Patented Jan. 15, 1946 UNI TED STATES "PATEN T F FI CEE Y2,392,940 ELECTRICAL commit-,FITTING Adolph olevin, BrooklynfN. y. Application August 5, 1943, Serial-No.fi91527 6 Claims. This invention `relates.-. zene1'ally to electrical conduit fittings or boxes and more particularly to devices of this class in Which-the-connection between the conduit and the-fitting Vor box is in stantaneously operated.

Among theprincipal-objects ofthe present inof a device-of theclass described in whichV the Vconnection between1A the conduit and the -tting or-box is accomplished without the use of threads on eithenof. the-parts.

Another object herein liesA in .fa-provision ci. a

structure-of the class described-in which vonly afsimple engaging and pushing operationis necessary to inter-connect the parts.

Another object -hereinlies in the provision -of the devices of the class described-in whichthe parts may be rapidly-disengaged Where necessary by the simple insertion of a-pin into the fitting or box.

An advantage which ows 4from the lfact-that the parts need not be provided with threads, j's that the workman or .installer Aneed onlyVA sever the end of the conduit-to form-the--prope1-length thereof and to engage the parts. No-threading need be -clone on the-job and the protective -rust- YresistingV coat or plating upon the conduit isnot -damagedor broken through as is the case :when A'threading is performed.

-Anotherobject herein lies in the provisicnbf -a conduit engaging fitting orv benin-whichthe gripof the tting or boxlincreasesyincorrela- AH.tion with the tension uponthe conduit.

A vstill further-object herein lies --inA the pro- Vision-of a structure of the vclass-Vdescribed-in whichV undesirable axial rotation-of :the-conduit is prevented after the same and engaged by the tting or box.

Another object herein lies in the provision of a conduit box in -Which the penetrationgof the Yconduit into the box is controlled and predetermined.

Another object herein lies inthe provision of -an electrical conduitV connectionwbox- Which-is or outdoor-use, and --Whenadapted for the-latter use, -has-provisio-n. for-preventing the entrance of-Water thereinfso -as to be substantially weatherf-tight.

A feature of the invention lies-in the fact that the conduit-receiving nipple portions'thereof are securely integrated with'the box-without the usev of-Welding, brazing or soldering,A and yet-the conhas `,become seated struction-is durable and readily-manufactured in large scale at low cost. Y fThese objects and other incidental Vends -and advantages will more fully appear in the-progress -as setup for outdc- Cl. A2785--182.1)

of this vdisclosure-and be pointedout in the ,ap-

Y.pended claims.

In v the drawings in .which similar .characters designate corresponding parts throughout the -several views:

`Figure-lis airont elevational view ci anembodirnent` 0fthe yinvention. in closed condition, oruse and engaging an end of a piece of conduit. -In this-viewthe-cover plate `is removed from the-box.

AFigure 2 isa top planview of,-:-Figure-l.

Figure 3` is a fragmentary central verticalgsectional` View as seen from the plane-3 3 onfFigure =2.

Figure fl-isla fragmentaryfsectional View as seen from the` plane d-e on Figure `3.

Figure 5 is atop plan View taken similarly to Figure 2 but with the conduit and the Weatherproofing cap removed.

Figure bis` an elevational view .ofthescored blank from whichr the grippingy element is 4subsequently formed.

jting element.

Figure'? isY a fragmentary central vertical sectional -view-showing schematically the rst stage inthe engagement of aV conduit end bythe-f1t- -Figure 8 is a viewcorresponding to Figure 7 l but shovvingthe second stage in the engagement Nment, lthe .gripping spring element.

Figure 10 is an elevational view ofthe conduit removing or spring releasing tool.

Figure 11 kis an enlarged fragmentary horizontal sectional View as Aseen 'from the plane ll-H on Figure 3.

Figure 12 is an enlarged fragmentary hori- Vzontal sectional View .as seen from ,the plane l2-i2 on Figure 3.

Figure 13 isa 'fragmentary vertical sectional view of a piece of stripA stock or va blank inthe first stage preparatoryfto the blanking and forming ,operations whichproduce theretainer vele- Figure -14 .,is a rfragmentary vertical .sectional view' showing the rst forming and blanking @operation in they production of the retaineraelement.

Figure 151 is a fragmentary` .verticalssectional View. .Showing ihe,;se9r 1dff0rming and; blanking operation in the production of the retainer element. Y

Figure 16 is a fragmentary vertical sectional view of a piece of strip stock or blank from which the nipple element is subsequently formed.

Figure 17 is a vertical sectional View showing a subsequent forming and blanking stage in the production of the nipple element.

Figure 18 is a vertical sectional view showing the completely ,formed sheared and blanked nippleelernent.Vv A y o In accordance with the preferred embodimentl of the invention, the electrical conduit fitting generally indicated by numeral 20 includes a nipple element 2|; a retainer element 22; and a gripping spring element 23. As will more fully appear hereinbelow, the fitting may also have associated therewith a weather-proof cap 24 and gasket 25.

Since the purpose of the electrical conduit fitting is to mechanically engage theend of an electrical conduit with either kanother end of an electrical conduit or with some connection box, it will be obvious to those skilled in the' art to which the present invention relates,`that the s present fitting element may be incorporated inv all manner of connection boxes or may be associated in an end to endA relationship so as to form a junction or connectorfor two juxtaposed ends of axiallyaligned conduits. By way of example, I have shown in thev drawings, the fitting element as 'indicated with connection to a socalled T box in which the` greatest length of the box is disposed substantially perpendicularly to theend of the conduit which enters the4 j box substantially centrally of one of the long walls thereof. Thus, ,in Figure 1A the connection box is generally indicated by numeral 26 and includes a top wall 21; a bottom wall 28;

end walls 29 and 39; and a rear wall 3|. The

forward portions of the top and bottom walls 21 and 28 are provided with threaded orificed ears 32 and 33, which are adapted to receive the attaching screws of the usual cover plate, well known inthe art, said screws and cover platev not being illustrated in the drawings for purposes of clarity. Having blank walls, the box 23 may have Vany suitable electrical device associated with the cover of the box (not shown) or as will be obvious to those skilled in thefart,

. any of the walls maybe provided with.knock `outs, or with additional lfitting elements for connectingu other conduits leaving the box in Y directions generally perpendicularY to the Vparticular wall of the box upon which such additional fitting elements are located;V The conduit generally indicated by numeral34 may be of the standard thick or thin wall type and it will be understood that the fitting elements in actual process are constructed in a range of sizes to coact' with the standard external diameters of thin or thick wall conduits.

The nipple element 2| is generally of cylinv drical shape and is preferably formed up" from sheet Amaterial such as vsteel or brass. YThus,theV

bodyportion 3.5 'of the'nipple element 2| has thefouteriwall 36 andthe inner wall31 thereof tapering toward the relatively outer end 38 there- 'of This taper or convergence of the walls is relatively of low order, as Vfor example, 'four degrees. Y

A' 'The outer end 38 ofthe nipple element 2'lrhas anyinwardly extending outer flange 39;l The inner verticaledge 40 of theange `39 hasan effective diameter'substantially equalto ci sligl'it-V ly greater than the effective external diameter of the particular size of conduit 34 with which it is desired the fitting 29 shall be used. Diametrically and oppositely arranged in the flange 39 are a pair of cut-outs 4| and 42 which serve to permit passage therethrough of the pin 43. This pin which is used to disengage the conduit 34 from the fitting 29 when desired is provided with a handle 44, and its operation will be de- 'scribedj fully hereinbelow. The cut-'outs 4| and 42-may be' produced by making a pair of L shaped cuts in the flange 39 and inwardly bending the tabs so formed, thereby forming the spring outer detents 45. and 45. The outer detents 45 0r 49 are adapted to prevent counterclockwise rotation'as` viewed in Figure 12 of the spring element `23. Y,

vAdjacent the outer end se, the body portion 35 ofthe nipple element 2| is provided with a pair of radially outwardly extending protuberances 4T and 48 which are adapted toV engage the weatherproofing cap 24. These protuberances may be produced by deforming the material of which the nipple is composed or by inserting sepi arate pins.

' 52, 53, 54 and 55.Y The innermost portions of the flange 5| which remain between the guides 52"-55 inclusive, form the conduit detents 55, 51,' 53 and 59; The guides 52-55 inclusive, have the inner opposed surfaces thereof perpendicularly disposed with relation to the inner ange 5 I, and the upper surfaces detents 53-59 inclusive. The distance T40 between anyrdiametrically opposite pair of guides 52, 53, 54 and 55, is substantially equal to or slightly greater than the effective external diameter of the particular size of conduit 34 which it is desired the fitting 29 shall be used. The'distance Vbetween any diametrically opposite portions of the conduit detents 56, 51, 58 and 59 is substantially equal to or slightly greater than the largest' internal diameter of the particular size of' conduit 34 with which it is desired the fitting 29 shallbeused,

y lThe retainer element22 (seerpFigure l5) comprises a base Elija nipple riniretaining rabb'et 6|, and an internally and outwardly tapered'nipple bodywretainingY neck 62. Theshape andsize of the rabbet 6| and the 'necki2V are such thatthey will receivein a 'force fit the"corresponding`portions of the rim 59 and the outer wall 36V of the body 35. By reason 'of this fit, movement ofthe nipple element 2| outwardly of vthe fitting 29 or upwardly in say Figure 3, is prevented bythe shape of the interfitting 'parts while movement of the nipple element in theopposite direction is prevented by friction due to the tight iit AsA an additional means of preventing inwardordownward movement'of the nipple element say in Figure 3 the portions of the baseIV 69 are 'swagediradially inwardly tov form the inward radial base projections generally indicated by reference character |53. As shown in the drawingsthe'basc 69 is Yvided with aseries of serrationsM'whicharebest 75 "seedin Figure 6,' whichthe"blank65from atrapa ne eating.. sans. eer-lei. 'iis ,later formed, is shown. The purpose Aof these serraltigris is to, decrease theeirecti've flexing diameter of the spring wire andto thereby increase itsresillones?, and to increase the'coeicient of friction between theinner surface of thehelical Ys'pril'lg and the outer wall of the conduit 34, In thefrm shownthe gripping element 23is in the 'form of a helical coil spring substantially one full turn. The transverse thickness of the wire blank E5, that is to say the distan'cebetween the inner 'surface 66 andthe outer surface 61 is such that'twice this `thickiflessH plus. the external dianleter of the :ndult 34 is slightly gr'etrtlln thi-` internal diameter ofthe nipple elnjlet (ZIllnelitely viil'lll/"aldlyA ofthe outer flange V39. The lgripping elefil-nt 23 Vis shown il lthe drawings as befiigwund in the Asaine direction as a right hand thread,` but this matter of chOice and the device 20`wi11 operate equallywell if theeleiiieni '213 is wound inthe opposite direction. The pitch of the spring element 23 is ,preferably such that 'its greatest length axially, 'in an distressed condition is 'substantially equal to or slightlyfgreater than the distance between the inner surface (lower surface a's viewed lin Figures 3 or 18)y of the outer ange and the inner surface v(upper surface as yvi'el'lvedin Figures 3 or 18) ofthe flange 5l'. Thus in neof the operable seated positions thereof the upper or outer end 6'8 of the gripping-spring element 23 may abut against 'thespring'ute'r detent45 (see Figure 12) while lthe lower or inner end 69'may abut against the spring inner detent 2 (seey Figure 1 1). 2 3 may beA installed'withinthe nipple element 2l by temporarily winding the same slightly about its Aaxis to thereby reduce the eifective'diameter of saideleinent, and inserting the same through the orifice formed vby the outer flange '39. While I have shown the gripping element as including one complete turn or `convoll'itionthis may be increased or decreased within certain limits, If more convolutions are used it may be necessaryto increase the length of the nipple element 2l, while reducing the spring length to less than one convolution may result in a reduction of the ultimate gripping area of the surface 66 against the outer wall of the conduit 34. As will appear as this disclosure proceeds most of the gripping takes place in the outer portions (the portions of least diameter) of the inner` tapered walls 31 of the nipple element 2 I.

The rapid andv eflicient fabrication of the device 29 is a relatively simple procedure.

The gripping elements 23 may be manufactured by taking an indeterminate length of square section spring wire 55 in its soft or annealed state and striking the serrations B4 therein, and then coiling the same about a mandrel (not shown) of a size substantially equal to the size of the conduit 34. Next the coil is stretched out to get the proper inter-convolution spacing. Then a cut is run along one side of the coil parallel to the axis of the coil, and the individual elements 23 sc formed are hardened and tempered.

The nipple element 2| may be produced by taking a piece of at stock 'I0 (see Figure 16) and drawing a portion thereof to the cup shape 1|, punching out the orice 12, and severing the cup 'H from the stock l0 along a circular line T3. The edge of the orice 12 is sheared and bent to form the detents 52-55 inclusive, and the edge 14 is sheared and bent to form the detents 45 and 46 and the protuberances 41 and 48. The edge 14 is bent inwardly through almost ninety degrees The gripping spring "element as', si, se and "Se,

' Figure y8) s whiletlie' 'body 1 35' 'is forced inwardly tcwaraits axisto lforrri'th'e proper taper vin'said body.' The bottom wall '1'5"'of thecup'll is forced upwardly as viewedin Figure lto cause it and the'sidewall tomusliroom'out'to formthe folded rim 50 (Figure 18).

The retainer velement 22 is formed from nat stock lli'an'd isdrajwn'and pun'ched'assh'own in -l'igure 1,4, A circular cut is made along tneline 11 'andthe 'disc v"is'removed. Another drawing 'of 'themater'ial bordering thje'lin'el edge 'il produces theshort cylindrical neck S2 with a taper toponforiri to the outer wall 36 just above the rim ai),

Assei'n'bly "of vthe parts including the installation 'of 'the spring and the swaging of the base as `previously described. complete the fabrication 'of the deVC 2U.

Operation Assuming that the conduit 34 has been cut oil substantiallyV square and theburrs removed, as best seeninFigure 7, the Aend 3b of theconduit 34 is inserted downwardly between the outer flange 39. The effective internal diameter (the distance between opposed faces 65) is either such as to allow the conduit 34 to pass downwardly within the element 23 therebetween or to catch hold on said element. Ii the conduit catches holdfit compresses-the spring element 23 causing it to approach a flattened condition (see AFigure 9)-. Vl/'hen the spring Vfbecor'nes flattened its effcllive linternal diameter in a plane'perpndculal to 'its axis becomes greater. This allows the' conduit `'to penetrate theV spring. l

Thecniiuit '24 is 'now Dass'e'd'dbwnwardly as viewed in Figure 7 between the inner spring deten'ts 52, 53,'5'4 and' 55 which act 'as guides'there- "fr'until 'the end Bstrikes the 'conduit de'tents This Aposition is shown in Fligur'e 3. Next 'the conduit is slightly vwithdrawn Afrom the nipple v element 2l which causes the gripping 'spring element 23"'to 'be drawn up vinto `tllen'arrower Vupper -portion of the body portion 35 (see AWhen the spring element 23 is thus `drawn into the narrower portion of the nipple 'element`2l 'sjai'd .gripping element 23 becomes 'wedged 'in' between the outer'surface 'ofthe 'conduit '34 and the innerwall 3i. The conduitis now in its so-called locked position.

In order to release the conduit 34 it is only necessary to insert the pin G3 through one of the cut-outs 4l or 42 so as to permit pressure upon the handle 44 to force the gripping element 23 into a more attened condition in the wider portion of the nipple element 2i adjacent the tops of the spring inner detents 52-55 inclusive. This condition is shown in Figure 9 and since the effective internal diameter of the gripping element 23 is now greater than the effective external diameter of the conduit 34, said conduit may be easily removed by elevating the same, as viewed in Figure 9.

Where it is desired to use the device 2l) in socalled out-door use, it becomes necessary only to slip on the conduit element 34, the weatherproof cap 24 containing the gasket 25 before the said conduit is inserted into the nipple element 2|. 'Il-he cap 24 is provided with known bayonet-type slots which permit the cap to be engaged upon the protuberances lll- 48, and drawn up snug until the gasket 45 forms a water-tight seal.

It may be seen that in the engagement of the conduit 34 in the device 20 that it is maintained in substantial alignment by the action of the inner surface 4U of the outer ange 39 and by the inner opposed surfaces of theguides or spring detents 52-55, inclusive. After" the grippingelement 23 has properly engaged -theouter surface of theV conduit 34, rotation ofithe conduit and gripping element is prevented by the engagement of the ends 68 Vand 69 of the spring element 23 against the nearest detents 45 and 45 and 52-55.

It may thus be seen that I have provided a novel and useful threadless conduit fitting which may be manufactured at W cost and yet which is durable and eihcient in use. Connection and disconnection of conduit ends with my device maybe rapidly and conveniently accomplished. Two of the fittings may be placed back to back and used as a coupling between aligned ends of different conduits.

Electric conductors of the usual type may be drawn through the conduit and into and out of the tting or the box with which it is associated in the usual manner. y Y

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim: f

1. For use with a conduit, a ttng comprising: a nipple element having a tapering internal Wall; and a gripping element in the form of a helical spring loosely positioned within said nipple element and between the outer Wall of said conduit and the inner Wall of said nipple element when said conduit is in an engaged position thereof Within said' nipple element, said helical spring directly contacting said conduit in the engaged position of the conduit.

2. For use with a conduit, a tting comprising: a nipple element'having a tapering internal wall; a gripping element in the form of a'helical spring loosely positioned within said nipple element and between the outer wall of said conduit and the inner wall of said nipple element when said conduit is in an engaged position'thereof within said nipple element; an inwardly extending ange disposed at the outer end of said nipple element; and a detent disposed within said Vnipple elementand depending from said ange, said detent being disposed in the path of rotation of said gripping element.

,3. An electrical conduit tting comprising: a

Y nipple element having a tapering inner wall; and

a helical spring gripping element loosely positioned Within said nipple element and adjacent said tapering wall, said gripping element having a serrated inner surface adapted to engage said conduit when said conduit is inserted into said nipple element.

4. An electrical conduit fitting comprising: a nipple element having a tapering inner Wall; and a gripping element loosely positioned within said nipple element and adjacent said tapering wall; said nipple element at one end thereof having an inner ange, projecting inwardly from the body portion of said nipple element, said ilange having a conduit detent extending in the path of travel of a conduit inserted into the other end of said nipple element. y

5. An electrical conduit iitting comprising: a nipple element having a tapering inner Wall; and agripping element loosely positioned within said nipple element and adjacent said tapering Wall; said nipple element at one end thereof having an inner ilange, projecting inwardly from the body portion of said nipple element, said flange having a conduit detent extending in the path of travel of a conduit inserted into the other end of said nipple element; said inner ilange having a spring inner detent disposed outwardly of said conduit detent and in the path oflrotation of rsaid gripping element.

6. In a device of the class described: a nipple element including a body element having an internally tapered wall, the inner end of said body having a folded peripheral rim extending radially outwardly from the body and radially inwardly to form a conduit detent extending into the path of travel of the conduit as inserted Within the nipple element; a gripping element loosely associated with said taperingwall; and a retainer element having a rim receiving rabbet and a base; said rim being disposed within said rabbet; portions of said base being swaged over to secure said rim in position Within said rabbet.

ADOLPH OLEVIN. 

